U.S. patent application number 12/208852 was filed with the patent office on 2009-03-19 for imaging positioning system having robotically positioned d-arm.
Invention is credited to Toby D. Henderson, Niek Schreuder.
Application Number | 20090074151 12/208852 |
Document ID | / |
Family ID | 40452819 |
Filed Date | 2009-03-19 |
United States Patent
Application |
20090074151 |
Kind Code |
A1 |
Henderson; Toby D. ; et
al. |
March 19, 2009 |
Imaging Positioning System Having Robotically Positioned D-Arm
Abstract
An imaging positioning system having a robotically positioned
support structure is provided. By utilizing a robotic arm, imaging
along multiple planes within a patient treatment room without
having to move the patient is provided. Such a configuration allows
multiple axis x-ray imaging, cone beam CT acquisitions having a
dynamic field of view, and PET imaging within the treatment room.
Rotation of the imaging panel on the support structure allows the
imaging system to simulate a gantry rotation when a fixed beam is
used for treatment. Beam line x-ray imaging is also provided by
tilting the imaging panel or by moving the support structure on
which the x-ray source is positioned. Laser distance scanning for
collision avoidance and force torque sensing movement enhance the
safety thereof. The support structure may be in the form of a ring
along which the imaging components may move.
Inventors: |
Henderson; Toby D.;
(Rockford, IL) ; Schreuder; Niek; (Bloomington,
IN) |
Correspondence
Address: |
REINHART BOERNER VAN DEUREN P.C.
2215 PERRYGREEN WAY
ROCKFORD
IL
61107
US
|
Family ID: |
40452819 |
Appl. No.: |
12/208852 |
Filed: |
September 11, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60972078 |
Sep 13, 2007 |
|
|
|
Current U.S.
Class: |
378/198 |
Current CPC
Class: |
A61N 2005/1052 20130101;
A61B 6/102 20130101; A61B 6/4458 20130101; A61N 2005/1061 20130101;
A61B 5/0064 20130101; A61B 6/037 20130101; A61B 6/4476 20130101;
A61B 6/4464 20130101; A61B 6/544 20130101; A61B 6/4441
20130101 |
Class at
Publication: |
378/198 |
International
Class: |
H05G 1/02 20060101
H05G001/02 |
Claims
1. An imaging positioning system, comprising: a support structure;
an imaging device positioned on the support structure; and a
robotic arm coupled to the support structure at a coupling between
the support structure and the robotic arm, the robotic arm
operative to move the support structure along multiple rotational
axes and at least one linear axis; wherein the orientation of the
imaging device relative to the coupling is adjustable.
2. The imaging positioning system of claim 1, wherein the position
of the coupling is adjustable relative to support structure,
thereby allowing adjustability of the orientation of the imaging
device relative to the coupling.
3. The imaging positioning system of claim 2, wherein the coupling
includes a coupling plate that is moveable along and relative to
the support structure.
4. The imaging positing system of claim 1, wherein the imaging
device is moveable along the support structure, thereby allowing
adjustability of the orientation of the imaging device relative to
the coupling.
5. The imaging positioning system of claim 4, wherein the support
structure is a ring structure formed by at least two segments that
pivot relative to one another to make a continuous ring in a first
pivoted state and to break the continuous ring in a second pivoted
state forming an opening between the two segments in the second
pivoted state.
6. The imagining positioning system of claim 4, wherein the support
structure is a ring structure and the imaging device is movable
relative to the ring structure about the entire circumference
defined by the ring structure.
7. The imaging device of claim 4, wherein the position of the
coupling is adjustable relative to the support structure.
8. The imaging device of claim 1, wherein the imaging device
includes two separate imaging components, each component
operatively mounted to the support structure, the two imaging
components are pivotable relative to each other.
9. The imaging device of claim 8, wherein the support structure is
segmented into two portions that are pivotally connected to one
another for relative angular movement therebetween, one component
is operatively mounted to one of the portions and the other one of
the components being operatively mounted to the other one of the
portions, the two components pivotable relative to each other via
the pivotal connection between the two support structure
segments.
10. The imaging device of claim 9, wherein the support structure
has a concave profile open on one side for receipt of a patient
therethrough for positioning the patient between the two imaging
components.
11. The imaging device of claim 8, wherein at least one of the two
imaging components is pivotally mounted to the support structure
such that pivotally mounted imaging component can be pivoted out of
alignment with the other one of the imaging components without
adjusting an orientation or a configuration of the support
structure.
12. The imaging device of claim 8, wherein the coupling between the
support structure and the robotic arm is positioned closer to one
of the imaging components than the other one of the imaging
components.
13. The imaging device of claim 1, further including a force torque
sensor and the robotic arm is operably configured such that
positioning of the support structure is controllable by pulling on
the support structure and is not autonomously controlled by the
robotic arm.
14. The imaging device of claim 1, further including a laser
distance tracking device, the laser distance tracking device
configured to sweep the volume defined by the support structure and
configured to sense the presence of any objects within the volume
defined by the support structure.
15. The imaging device of claim 14, wherein the laser distance
tracking device further configured to determine an envelope defined
by a patient positioned within the volume defined by the support
structure, the imaging device being configured to prevent any
portion of the imaging device from entering the envelope defined by
the patient.
16. The imaging device of claim 15, wherein the laser distance
tracking device includes a laser scanner and a control including a
patient positioning system collision avoidance algorithm that takes
the data from the laser scanner and ensure that no object of the
imaging device is allowed to enter the envelope defined by the
patient.
17. An imaging positioning system, comprising: a support structure;
an imaging device positioned on the support structure; and a
robotic arm coupled to the support structure at a coupling between
the support structure and the robotic arm, the robotic arm
operative to move the support structure along multiple rotational
axes and at least one linear axis; wherein the coupling between the
support structure and the robotic arm is a uniform tool changing
coupling such that the support structure can be automatically
released from and coupled to the robotic arm.
18. The imaging positioning system of claim 17, further comprising
an auxiliary support structure independent from the support
structure, the auxiliary support structure and robotic arm forming
an auxiliary coupling therebetween, the auxiliary coupling between
the auxiliary support structure and the robot arm is a uniform tool
changing coupling such that the auxiliary support structure can be
automatically released from and coupled to the robotic arm using
the same coupling structure that robotic arm uses to form the
coupling with the support structure.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This patent application claims the benefit of U.S.
Provisional Patent Application No. 60/972,078, filed Sep. 13, 2007,
the teaching and disclosure of which are hereby incorporated in
their entireties by reference thereto.
FIELD OF THE INVENTION
[0002] This invention generally relates to patient imaging systems,
and more particularly to patient imaging systems for use in
therapeutic radiation treatment operations such as proton and ion
beam treatment.
BACKGROUND OF THE INVENTION
[0003] Continuing advances in medical science, and specifically in
the field of radiation treatment, have allowed the development of
more precise, targeted treatment options for patients with tumorous
cells that results in less radiation being applied to healthy
cells. However, for each of the two main types of radiation
treatment, i.e. radiosurgery and radiotherapy, precise imaging of
the tumor location is critical to ensure the radiation is delivered
only to the target area. This is particularly important in
radiosurgery because of the intense doses of radiation that are
delivered to the patient are intended to destroy tumorous cells or
otherwise treat the target region. While the amount of radiation
delivered to a patient during radiotherapy is typically about an
order of magnitude smaller than used in radiosurgery, for example
to treat early stage cancers, precise delivery to the cancerous
cells is still very important to minimize the negative impact on
the patient. As such and for ease of understanding, the following
description will use the term radiotherapy to refer to both
radiosurgery and radiotherapy.
[0004] In each of these radiation treatment operations, it is
necessary to determine with precision the location of the target
region and surrounding critical structures relative to the
reference frame of the treatment device. It is also necessary to
control the position of the radiation source so that its beam can
be precisely directed to the target tissue while avoiding
surrounding healthy tissue, with control of propagation in and
through other body structures.
[0005] To effect such beam position control, frameless stereotactic
radiotherapy systems have been developed, which implement
image-guided radiotherapy using a robot. An image-guided robotic
system provides the requisite beam position control for accurate
delivery of therapeutic radiation, while eliminating the need for
rigid stereotactic frames. Such image-guided robotic systems
typically include a treatment beam generator mounted onto a robot
and a controller. The treatment beam generator provides precisely
shaped and timed radiation beams. Using pre-treatment scan data, as
well as treatment planning and delivery software, the controller
acquires information regarding the pre-treatment position and
orientation of the treatment target region. The patient is usually
placed on a support device, such as a couch or a table. During
treatment, an imaging system repeatedly measures the position and
orientation of the target relative to the x-ray source. Prior to
the delivery of radiation at each delivery site, the controller
directs the robot to adjust the position and orientation of the
treatment beam generator, in accordance with the measurements made
by imaging system, so that the requisite dose of the treatment beam
can be applied to the treatment target within the patient.
[0006] FIG. 1 schematically illustrates one such radiotherapy
system 10 described in U.S. Pat. No. 7,154,991 B2, entitled Patient
Positioning Assembly For Therapeutic Radiation System, assigned to
Accuray, Inc. This system 10 includes a robot 12 having an
articulated arm assembly 13, a therapeutic radiation source 14
mounted at a distal end of the articulated arm assembly 13 for
selectively emitting therapeutic radiation, an x-ray imaging system
and a controller 18.
[0007] The x-ray imaging system generates image data representative
of one or more near real time images of the target. The x-ray
imaging system includes a pair of diagnostic x-ray sources 17, and
a pair of x-ray image detectors (or cameras) 21, each detector
located opposite an associated one of the x-ray sources 17. A
patient support device (or treatment table) 19 supports the patient
during treatment, and is positioned between the two x-ray cameras
21 and their respective diagnostic x-ray sources 17.
[0008] The imaging system generates, in near real time, x-ray
images showing the position and orientation of the target in a
treatment coordinate frame. The controller 18 contains treatment
planning and delivery software, which is responsive to
pre-treatment scan data CT (and/or MRI data and/or PET data and/or
ultrasound scan data) and user input, to generate a treatment plan
consisting of a succession of desired beam paths, each having an
associated dose rate and duration at each of a fixed set of
nodes.
[0009] Prior to performing a treatment on a patient, the patient's
position and orientation within the frame of reference established
by the x-ray imaging system must be adjusted to match the position
and orientation that the patient had within the frame of reference
of the CT (or MRI or PET) scanner that provided the images used for
planning the treatment. It is desirable that this patient alignment
be performed to within tenths of a millimeter and tenths of a
degree for all six degrees of freedom.
[0010] Unfortunately, with such a mounted imaging system 10, the
imaging views that are able to be taken are limited in orientation.
Further, since the imaging system 10 is mounted, requiring two
x-ray sources 17 and two cameras 21, the patient must be moved
between the cameras 21 to image different parts or areas of the
body. Any such movement of the table 19 once set up runs the risk
of disturbing the alignment, i.e. patient's position and
orientation, which will then need to be re-confirmed and set-up
before further treatment is begun. Still further, such an imaging
system 10 places constraints on the treatment envelope within the
treatment room so as to avoid collisions between the table 19 and
the cameras 21. These camera structures also take up, and therefore
limit, the available space within the treatment room, obstructing
free movement of the technician or other medical personnel when in
the treatment room.
[0011] Additional radiotherapy systems are illustrated in U.S.
Patent Publication Number 2007/0230660, entitled Medical
Radiotherapy Assembly, by Klaus Herrmann. The '660 publication
illustrates a first system where the imaging system is mounted to
the therapeutic radiation source such that the x-ray source and
x-ray detector of the imaging system rotate only angularly about a
longitudinal axis defined by the particle beam of the therapeutic
radiation source.
[0012] Again, unfortunately, with this mounted imaging system
arrangement, the imaging views that are able to be taken are
limited in orientation to being angularly positioned about the
particle beam. Therefore, it is impossible in this system to align
the imaging system, namely the x-ray source and x-ray detector,
with the direction of particle beam.
[0013] A second system is disclosed in the '660 publication that
includes an imaging system including an x-ray source and x-ray
detector mounted to a support arm that is C-or U-shaped. This C- or
U-shaped allows the support arm to be open on one side. This
support arm is mounted to a six axes robot.
[0014] While this arrangement permits some improved positioning of
the imaging system over the previous systems, the imaging system of
this radiotherapy system (i.e. both he x-ray source and the x-ray
detector) the x-ray detector of the imaging system cannot be used
to help align or check alignment of the particle beam relative to
the target area. Particularly, the x-ray source of the imaging
system would be in the way of a particle beam line x-ray source of
the therapeutic radiation source.
[0015] Instead, if the alignment of the particle beam is to be
checked prior to therapy, a secondary independent x-ray detector
must be positioned in place of the x-ray detector of the imaging
system to cooperate with a particle beam line x-ray image prior to
initiating the therapy of the patient. Again, this unfortunately,
requires additional set-up of another imaging device which
inherently imports potential error in the alignment of the particle
beam.
[0016] Further, to adjust the orientation of the imaging system
relative to a patient, the entire support arm and robot must be
moved relative about the patient. Unfortunately, rotating the
entire support arm from the mounting point requires overcoming
substantial rotational inertia due to the size and weight of the
support arm and the moment arm created by offsetting the x-ray
detector and x-ray source from the point of rotation of the support
arm.
BRIEF SUMMARY OF THE INVENTION
[0017] Embodiments of the present invention provide a new and
improved imaging positioning system. More particularly, embodiments
of the present invention provide new and improved imaging
positioning systems that overcome one or more of the
above-described problems existing with current imaging systems
utilized for therapeutic radiation treatment operations. More
particularly, embodiments of the present invention provide new and
improved imaging positioning systems having a robotically
positioned support structure for carrying and position imaging
equipment.
[0018] In one embodiment, the support structure is a D-arm that
houses an x-ray source on one leg and a radiographic imaging panel
on the other. In another embodiment the D-arm houses a cone beam CT
source on one leg and an imaging panel on the other. Still other
embodiments of the present invention utilize positron emission
tomography (PET) cameras mounted on each of the legs of the D-arm
to allow PET imaging. Still other embodiments of the present
invention utilize a combination of these imaging technologies to
satisfy the imaging requirements of the therapeutic radiation
treatment operations used therewith.
[0019] In one embodiment of the present invention, the imaging
system utilizes a selectively compliant articulated robot arm
(SCARA) type robot that provides five rotations and one linear
translation axis. To maximize the available space within a
treatment room, an embodiment of the present invention mounts the
SCARA type robot in the ceiling of the treatment room. The SCARA
type robot is then able to position the support structure so that
the patient is within a volume defined by the support structure and
the imaging components of the imaging equipment carried thereon.
This allows imaging orientations along nearly every plane without
requiring movement of the patient or the positioning table on which
the patient has been secured.
[0020] For x-ray imaging, only one x-ray source and one
radiographic imaging panel is required. By using a SCARA type high
payload, high precision robot to position the D-arm on which the
imaging equipment is mounted, very high precision and repeatable
positioning of the imaging equipment is enabled. This greatly
simplifies the commissioning process. As such, embodiments of the
present invention may be used to acquire static x-ray images along
multiple axis through the treatment room isocenter. This provides a
more adaptable solution and will allow for easier integration with
multiple patient alignment systems that control the positioning of
the patient and the treatment beam. One such patient positioning
system is described in co-pending application Ser. No. 60/972,107,
filed on Sep. 13, 2007, the teachings and disclosure of which are
hereby incorporated in their entireties by reference thereto.
[0021] In an alternate embodiment of the present invention, cone
beam CT (CBCT) acquisition is made possible by dynamically rotating
the D-arm about the patient in multiple planes. Indeed, in an
embodiment of the present invention the center of rotation during
CBCT acquisition between the source and the imaging panel is
provided by the SCARA robot. As such, the technician or medical
personnel is able to define a point of rotation for the D-arm,
which allows the technician or medical personnel to define or
adjust the field of view (FOV) provided by the CBCT. If a bigger
FOV is required or desired, the point of rotation of the D-arm
controlled by the robot will be closer to the imaging panel, while
a smaller FOV will be provided by defining a point of rotation that
is farther from the imaging panel. Further, the fact that the CBCT
acquisition can be done in multiple planes with an embodiment of
the system of the present invention, CBCT acquisitions are now able
to be performed on the patient while the patient is in the
treatment position. The control of the imaging system of the
present invention also allows for CBCT acquisitions with the
patient positioned in a seated position. This enabled in one
embodiment by positioning the D-arm to allow acquisition of CBCT in
the horizontal plane.
[0022] In an embodiment of the present invention, a mechanism is
provided to allow rotation of the imaging panel on the support
structure about the x-ray beam axis. This allows the imaging system
to simulate a gantry rotation when a fixed proton beam, that cannot
rotate, is used. The classical way of using static radiographic
images is to have the imaging panels in a fixed orientation with
respect to the fixed reference coordinate system in the treatment
room. When the patient is moved, instead of the beam (gantry), then
the radiographic image obtained with the fixed panel will not align
with the reference image obtained from the treatment planning
system. In one embodiment of the present invention, the imaging
panel is rotated about the x-ray axis to simulate the effect of a
beam rotation.
[0023] In one embodiment of the present invention, the support
structure is divided into separate segments or portions allow the
imaging panel and x-ray source to be moved out of the same plane of
the imaging panel. This allows the imaging panel on the support
structure to be used for a beam line x-ray image. In another
embodiment the image panel mount on the support structure includes
a mechanism to allow the imaging panel itself to be tilted out of
the x-ray beam axis of the x-ray source mounted on the support
structure so that the imaging panel can be positioned perpendicular
to the proton beam axis without the x-ray source hitting the beam
delivery nozzle during beam line x-ray imaging.
[0024] In an embodiment of the present invention, an image panel
mount will allow the imaging panel to tilt out of the plane of an
x-ray beam axis so that the imaging panel can be positioned
perpendicular to a proton beam axis without the x-ray source
hitting the beam delivery nozzle. In other words, the support
structure and imaging panel will be rotated relative to one another
such that the image panel remains in its same location relative to
a patient, while transitioning the x-ray source out of line with
the previous axis that it maintained. Thus, a new x-ray source
associated with the beam delivery nozzle can be aligned with the
imaging panel to properly align the beam delivery nozzle relative
to the target region of the patient.
[0025] To ensure that no object will collide with the support
structure, one embodiment of the system of the present invention
utilizes a laser distance tracking device mounted on the support
structure. During use of the imaging system, the laser distance
tracking device will sweep over the volume enclosed by the support
structure so that it may sense the presence of any objects that
come in close proximity to any mechanical part of the imaging
system. This laser distance scanner is also used in an alternate
embodiment to determine the patient's surface envelope for use with
the imaging system, patient positioning system and treatment
system's collision avoidance control algorithms.
[0026] In an embodiment of the present invention a force torque
sensor is included between the robot wrist and the support
structure. All motions, except for the dynamic CBCT acquisitions,
will then be under force torque control. This means that none of
the motions about the patient to get the support structure in
position will be autonomous, i.e., the imaging positioning system
will only move along the path that the technician or other medical
personnel pulls it.
[0027] In further alternative embodiments, the support structure is
mounted to the SCARA robot at a coupling and an imaging device is
mounted to the support structure. In a preferred embodiment, an
orientation of the imaging device relative to the coupling between
the SCARA robot and the support structure is adjustable. This
allows for further precision in the operation of the imaging
positioning system and particularly positioning the imaging device
relative to a target area of a patient.
[0028] In a further embodiment, the support structure is a support
ring, which is a ring like structure that is preferably a
continuous ring. The support ring allows for rotating the
orientation of the imaging device 360 degrees about a central axis.
In a preferred embodiment, the imaging device may move relative to
the support ring to adjust the position of the imaging device
components relative to the coupling and the SCARA robot. This
arrangement greatly reduces the number of components of the overall
imaging positioning system that must be moved to make some
adjustments of the orientation of the imaging device.
[0029] Further yet, in some embodiments, the support ring is formed
by a pair of segments or portions that are pivotally connected to
one another. This allows the support ring to pivot between
different pivoted states, namely a closed pivoted state where the
support ring is a continuous ring and a second open pivoted state
where the support ring is broken, thereby forming a mouth between
the ends of the segments of the support ring. This allows the
support ring to be more easily positioned about a patient. Once
positioned about the patient, the support ring can be transitioned
to the closed pivoted state where the support ring continuously
surrounds an axis defined by the patient.
[0030] In another embodiment, the coupling between the support
structure and the robotic arm is adjustable such that the
orientation of the imaging device is adjustable relative to the
coupling by adjusting the location of the coupling to the support
structure. More particularly, in one preferred embodiment, the
coupling includes a coupling plate that is moveable relative to and
along the support structure.
[0031] Other aspects, objectives and advantages of the invention
will become more apparent from the following detailed description
when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The accompanying drawings incorporated in and forming a part
of the specification illustrate several aspects of the present
invention and, together with the description, serve to explain the
principles of the invention. In the drawings:
[0033] FIG. 1 schematically illustrates a frameless radiotherapy
system, known in the prior art;
[0034] FIG. 2 is an isometric illustration of an embodiment of an
imaging positioning system constructed in accordance with the
teachings of the present invention;
[0035] FIG. 3 is an isometric illustration of the imaging
positioning system of the embodiment illustrated in FIG. 2
reoriented to illustrate additional features thereof,
[0036] FIG. 4 is an isometric illustration of an embodiment of the
D-arm utilized with the imaging positioning system of the
embodiment of FIG. 1 configured to perform x-ray imaging;
[0037] FIG. 5 is an isometric illustration of the D-arm illustrated
in FIG. 4 reoriented to illustrate additional features thereof;
[0038] FIG. 6 is an isometric illustration of the D-arm of FIG. 4
reoriented to illustrate additional features thereof;
[0039] FIG. 7 is a side view illustration of an alternate
embodiment of a D-arm configured for x-ray imaging and beam line
x-ray imaging;
[0040] FIGS. 8-10 are front view illustration of an alternate
embodiment of the imagining positioning system of the present
invention illustrating the ability for the support structure to
move relative to the robotic arm; and
[0041] FIGS. 11-14 illustrate an alternative embodiment of an
imaging positioning system that utilizes a support ring for
supporting the imaging components of the system.
[0042] While the invention will be described in connection with
certain preferred embodiments, there is no intent to limit it to
those embodiments. On the contrary, the intent is to cover all
alternatives, modifications and equivalents as included within the
spirit and scope of the invention as defined by the appended
claims.
DETAILED DESCRIPTION OF THE INVENTION
[0043] Turning now to FIG. 2, there is illustrated an embodiment of
an imaging positioning system 100 constructed in accordance with
the teachings of the present invention. While the following
description will describe embodiments of the imaging positioning
system in relation to its use in therapeutic radiation treatment
operations and facilities, those skilled in the art will recognize
that such embodiments and operating environments are provided by
way of example only, and not by way of limitation.
[0044] In the illustrated embodiment, the imaging positioning
system 100 utilizes a selectively compliant articulated robot arm
(SCARA) type robot 102 that provides five rotations and one linear
translation axis. Other embodiments of the present invention may
utilize a standard six axis robot. The SCARA type robot 102 of the
illustrated embodiment includes an upper arm portion 104, a lower
arm portion 106, a wrist portion 108 and a coupling portion 110.
Linear translation is provided along a mounting track 112 by base
portion 114. To maximize the available space within the treatment
room of the therapeutic radiation treatment center, a preferred
embodiment of the present invention installs the mounting track 112
in the ceiling so that the imaging system 100 may be moved up and
out of the way when not needed so as to not inhibit the movement of
any of the technicians, medical personnel, or the patient within
the treatment room.
[0045] The imaging positioning system 100 utilizes a support
structure in the form of a D-arm structure 116 on which the imaging
equipment is mounted. In the embodiment illustrated in FIG. 2, this
imaging equipment has two separate primary components shown as an
x-ray source 118 and an imaging panel 120, each component is
mounted to an opposed one of legs of the D-arm. Other embodiments
of the present invention utilize other imaging devices to allow
cone beam CT (CBCT) acquisition, positron emission tomography (PET)
imaging, etc. as will be discussed more fully below. Still further,
other embodiments of the present invention utilize multiple imaging
device technologies mounted on the D-arm structure 116 to provide
multiple types of imaging, for example, both an x-ray source 118
and imaging panel 120 and a pair of PET cameras to allow PET
scanning during the treatment operation.
[0046] FIG. 3 illustrates the same embodiment of the imaging
positioning system 100 illustrated in FIG. 2, but rotated so that
details of the base portion 114 and mounting track may be visible.
The base portion 114 (portions of which have been removed for
clarity of illustration) provides precise linear movement along
mounting track 112. In one embodiment this mounting track 112 is
positioned within the treatment room ceiling perpendicular to the
beam treatment plane. This allows the robot 102 to approach the
patient with the D-arm structure 116 from either direction to allow
image acquisition in multiple planes.
[0047] The D-arm structure 116 is illustrated in greater detail in
FIG. 4 to which reference is now made. In this embodiment of the
D-arm structure 116, a pair of frame members 122, 124 are joined by
cross braces 126, 128, 130. Mounting structure 132 is also joined
to each of frame members 122, 124 and provides a mounting coupling
point for the coupling portion 110 of the SCARA robot 102 (see FIG.
2). This coupling may be a rigid coupling such as may be provided
by bolts or other appropriate fasteners, or may be a dynamic,
releaseable coupling such as may be provided by a pneumatic
coupling known in the art. A dynamic, releasable coupling would act
as a uniform tool changing coupling that would shall allow for the
SCARA robot 102 to be easily and automatically coupled to and
uncoupled from other imaging systems, such as illustrated in FIG.
11-14.
[0048] Further, as illustrated in FIGS. 8-10, the D-arm structure
116 may be mounted to the SCARA robot 102 for linear movement
relative to coupling portion 110. More particularly, mounting plate
132 can move linearly about D-arm structure 116. In other words,
the mounting or coupling plate 132 can move laterally between the
leg portions of the D-arm and those laterally relative to x-ray
source 118 and imaging panel 120. Thus, as illustrated by the
progression of FIGS. 8-10, once positioned over a patient 154, the
D-arm structure 116 can be moved laterally relative to SCARA robot
102 such that the patient 154 is closer to the x-ray imaging panel
120 than to the x-ray source 118 (FIG. 8), the patient 154 is
substantially equally positioned between the x-ray source 118 and
the x-ray imaging panel 120 (FIG. 9), or the patient 154 is closer
to the x-ray source 118 than to the x-ray imaging panel 120 (FIG.
10). It should be noted that this linear translation of the D-arm
structure 116 in one embodiment can be done without any movement of
the SCARA robot 102 relative to the patient 154.
[0049] In one embodiment, the mounting plate 132 is moveable
relative to frame members 122, 124 to laterally position the D-arm
structure 116 relative to the SCARA robot 102. This allows for
adjusting the orientation of the D-arm structure 116 and
consequently the imaging device relative to the coupling between
the D-arm and the SCARA robot 102. The mounting plate 132 may be
driven by a linear actuator (not shown) to position the mounting
plate 132 relative to the frame members 122, 124.
[0050] In alternative embodiments, particularly where the D-arm
structure 116 is not moveable relative to the SCARA robot 102, the
D-arm 116 may be mounted in an offset position relative to coupling
portion 110 of the SCARA robot 102, such as illustrated by the
FIGS. 2 and 9 and the position of mounting plate 132 in FIG. 4.
This offset configuration is provided by having mounting plate 132
positioned laterally closer to x-ray imaging panel 120 rather than
x-ray source 118.
[0051] A mounting bracket 134 is also provided between frame
members 122, 124 at one end thereof for mounting the x-ray source
118 thereon. This mounting bracket 134, as well as a mounting
bracket (not shown) on the other end of frame members 122, 124 for
mounting of the imaging panel 120 also provides structural support
and adds rigidity to the D-arm structure 116.
[0052] As may be seen in FIGS. 5 and 6 (in which the mounting
bracket has been removed), the imaging panel 120 in the illustrated
embodiment is not mounted directly to either of frame members 122,
124, but instead is mounted to a motor 136. As illustrated in FIG.
6, imaging panel 120 is actually mounted to a mounting structure
138 that is coupled to the output shaft of motor 136. This allows
rotation of the imaging panel 120 on the D-arm structure 116.
Specifically, motor 136 is able to rotate imaging panel 120 about
the x-ray beam axis illustrated by line 140.
[0053] This allows the imaging system 100 to simulate a gantry
rotation when a fixed proton beam that cannot rotate is used during
the therapeutic operation. The classical way of using static
radiographic images is to have the imaging panels in a fixed
orientation with respect to the fixed reference coordinate system
in the treatment room. When the patient is moved, instead of the
beam (gantry) and the radiographic image is obtained with the prior
fixed panel, the image will not align with the reference image
obtained from the treatment planning system. In this embodiment of
the present invention, this problem is solved by rotating the
imaging panel 120 about the x-ray axis 140 to simulate the effect
of a beam rotation.
[0054] In embodiments that utilize rigid frame members 122, 124 and
that fix the imaging panel 120 and the x-ray source 118 along the
x-ray beam axis 140, it is impossible to use the same imaging panel
120 for a beam line x-ray image in a treatment center. This is
because such imaging requires the imaging panel be positioned
perpendicular with the proton beam axis, and with a fix mount of
the x-ray source 118 and the imaging panel 120 on the D-arm
structure 116 the x-ray source 118 will collide with the beam
delivery nozzle of the treatment beam when the imaging panel is
moved into proper position.
[0055] However, in an embodiment of the present invention the image
panel mount 142 will allow the imaging panel 120 to tilt out of the
plane of the x-ray beam axis 140 so that the imaging panel 120 can
be positioned perpendicular to the proton beam axis without the
x-ray source 118 hitting the beam delivery nozzle. In one
embodiment to the present invention the image panel mount 142 will
only need to provide a tilt angle of less than approximately 45
degrees, and preferably approximately 30 degrees out of the x-ray
beam axis 140. This will allow adequate clearance between the x-ray
source 118 and the beam delivery nozzle of the proton beam
treatment device when the imaging panel 120 is positioned
perpendicular to the proton beam axis, thereby allowing the beam
line x-ray image to be taken.
[0056] In an alternate embodiment of the D-arm structure 116'
illustrated in FIG. 7, the frame members 122' include a hinged
portion 144 and a drive mechanism 146. In this embodiment the x-ray
source 118 is able to be rotated out of the way of the ion beam
delivery nozzle when the imaging panel 120 is positioned
perpendicular to the proton beam axis. This will then allow beam
line x-ray imaging using the imaging panel 120 while avoiding a
collision between the x-ray source 118 and the beam delivery
nozzle. Again, this is another structural arrangement that permits
adjustment of the orientation of the imaging device relative to the
coupling between the SCARA robot 102 and the D-arm structure
116.
[0057] While FIG. 7 clearly shows that the mounting arrangement of
the x-ray source 118 and x-ray imaging panel 120 allows for the
x-ray source 18 to be rotated out of line with the x-ray imaging
panel 120 to allow beam line x-ray imaging to use the imaging panel
120, alternative embodiments of the invention are not limited to
this location of the hinge or pivot point for rotating the x-ray
source 118 out of alignment with imaging panel 120. For example and
with reference to FIG. 4, the x-ray source 118 may pivot relative
to the arm portion 147 that extend perpendicularly to arm portion
149 of the D-arm structure 116 to which the x-ray source 118 is
mounted.
[0058] The imaging positioning system 100 of the present invention
will not only allow the acquisition of static x-ray images along
multiple axis through the treatment room isocenter, but will also
allow for cone beam CT acquisition. These CBCT acquisitions are
achieved by controlling the SCARA robot 102 to dynamically rotate
the D-arm structure 116 about the patient in multiple planes.
Further, because the SCARA type robot 102 is used to position and
rotate the D-arm structure 116, a dynamic field of view (FOV) for
the CBCT acquisitions is possible. That is, since the center of
rotation between the x-ray source 118 and the imaging panel 120 for
CBCT acquisitions are determined by the SCARA robot 102, the
technician or medical personnel may define a point of rotation that
will control the FOV. If a larger FOV is required, the point of
rotation of the D-arm structure 116 about the patient may be user
defined to be closer to the imaging panel 120. If a smaller FOV is
required, the point of rotation of the D-arm structure 116 about
the patient may be user defined to be closer to the x-ray source
118 and farther from the imaging panel 120. Typical CBCT systems,
to the contrary, rotate about a fixed point in space. As such,
their FOV is also fixed.
[0059] A further advantage of the system 100 of the present
invention is that CBCT acquisitions may be obtained while the
patient is in the treatment position. That is, because the SCARA
robot 102 can dynamically position the D-arm structure 116 to
provide CBCT acquisitions in multiple planes, such CBCT
acquisitions may be done in the treatment position. Still further,
these CBCT acquisitions may be performed with the patient in a
seated, i.e. upright, position. This is made available in the
system of the present invention because the SCARA robot 120 can
dynamically position the D-arm structure 116 to acquire a CBCT in
the horizontal plane.
[0060] As discussed briefly above, positron emission tomography
(PET) cameras may be mounted in place of the x-ray source 118 and
the imaging panel 120, or may be mounted to the D-arm structure 116
in addition to or in place of the x-ray source 118 and imaging
panel 120. Because the SCARA robot 102 can dynamically position the
D-arm structure 116 within the treatment room while the patient is
being actively treated, PET imaging can be performed in the
treatment room without moving the patient into a separate PET
scanner. This is made possible by the D-arm structure 116 by
positioning the PET cameras at diametrically opposed positions
thereon. This is required because during the annihilation process,
two photons are emitted in diametrically opposing directions. These
photons are registered by the PET cameras as soon as they arrive
and the data is forwarded to a processing unit which decides if the
two registered events are selected as a so-called coincidence
event. All such coincidences are forwarded to an image processing
unit where the final image data is produced via image
reconstruction procedure well known in the PET scanning art.
[0061] In an embodiment of the present invention as illustrated in
FIGS. 8-10, a laser distance tracking device, such as a laser
scanner 148, is mounted on the D-arm structure 116. This laser
scanner 148 will sweep over the volume 150 enclosed by the D-arm
structure 116. The laser scanner 148 will sense the presence of any
objects that come in close proximity of any mechanical part of the
D-arm structure 116 within volume 150. The SCARA robot control will
receive the scanner data so as to control the position of the D-arm
structure 116 to prevent objects from coming in close proximity or
contact with any mechanical part on the D-arm structure 116. The
output data from the laser scanner may also be exported to a
patient positioning system collision avoidance algorithm. In such
an embodiment, the laser scanner 148 of the imaging system 100 will
scan over the patient 154 prior to the start of a treatment to
determine the envelope 152 occupied by the patient 154. Once this
envelope 152 has been determined, the patient positioning system's
collision avoidance algorithm will ensure that no object is allowed
to enter the envelope 152 during the treatment process.
[0062] In one embodiment of the present invention the coupling
portion 110 of the SCARA robot 102 will include a force torque
sensor. In such an embodiment, all motions of the SCARA robot 102
and the D-arm structure 116 will be under force torque control,
except for dynamic CBCT acquisitions. In such an embodiment none of
the motions about the patient to position to the D-arm structure
116 in position will be autonomous. Instead, positioning of the
D-arm structure 116 by the SCARA robot 102 will be controlled by a
user pulling the D-arm structure 116 into position.
[0063] With reference to FIG. 11, an alternative embodiment of an
imaging positioning system 200 is illustrated. The imaging
positioning system 200 is similar to the prior imaging positioning
systems described previously in many respects. For example, the
imaging positioning system 200 incorporates a SCARA robot 102 for
robotically positioning another embodiment of a support structure
for carrying and positioning imaging equipment.
[0064] In this embodiment, the support structure is support ring
216 that forms a continuous ring that surrounds an entire
360.degree. for providing additional positioning configurations of
x-ray source 118 and x-ray imaging panel 120 relative to a patient
154. While illustrated as a circular support ring 216, support ring
216 is intended to be broad enough to encompass other annular or
ring-type structures that may be polygonal in shape, oblong,
elliptical, oval, etc. while still substantially forming a ring.
Further, the ring need not necessarily form or be able to form an
entire continuous ring.
[0065] The illustrated support ring 216 in FIGS. 11 and 12 forms a
continuous fixed ring. As it is a continuous ring, the support ring
216 must be positioned (illustrated by double arrows 217) relative
to the patient 154 by moving along a path 219 (illustrated as a
dashed line) defined by the patient 154. As illustrated in FIG. 12,
the patient 154 is laying on a flat support such as a couch or a
bed such that path 219 is substantially linear. Thus, the support
ring 216 can be moved linearly along path 216 so as to take x-ray
images of desired locations of patient 154.
[0066] The illustrated support ring 216 is similar to the D-arm
structure 116 of the previous embodiments, in that it is formed
from a pair of frame members 222, 224 that are spaced apart from
and connected to one another by cross-braces 226, 228, 230.
Further, the x-ray source 118 and x-ray imaging panel 120 can be
mounted to the support ring 216 in identical fashion as in the
embodiments described previously with regard to the D-arm structure
116. Additionally, the support ring 216 may include a mounting
structure 232 similar to mounting structure 132 of previous
embodiments.
[0067] In one embodiment of the imaging positioning system 200 of
FIGS. 11 and 12, the support ring 216 can rotate, typically via
mounting structure 232, about an axis of rotation 231 relative to
coupling portion 110. This additional degree of freedom, allows the
x-ray source 118 and x-ray imaging panel 120 to be rotated about
the patient 154 to vary the angle at which x-ray images are taken
of the patient 154. This degree of freedom is preferably an entire
360.degree. about axis 231 and preferably permitted in either a
clockwise or counter-clockwise direction about axis 231 (i.e. as
illustrated by double arrow 233 in FIG. 11). More particularly,
this allows the x-ray source 118 and x-ray imaging panel 120 to
take x-rays from substantially any direction along or parallel to a
plane defined by axis of rotation 231.
[0068] A further embodiment of a support ring 216' is illustrated
in FIGS. 13 and 14. Support ring 216' is similar to support ring
216 except that the support ring 216' is formed by a pair of ring
portions 254, 256, i.e. segments, that pivot relative to one
another between first and second pivotal states. Ring portion 256
acts as a hinged portion that pivots relative to ring portion 254.
A drive mechanism 246 drives the two portions 254, 256 relative to
one another to open and close the support ring 216'. In the open
pivotal state (see FIG. 14), a mouth is formed between the distal
ends of the ring portions 254, 256.
[0069] This configuration allows for more easily positioning the
support ring 216' relative to a patient. Instead of being required
to move along an axis defined by a patient and passing over the
head or feet of the patient first, this clam version of the support
ring 216' can be opened (as illustrated in FIG. 14) such that it
can be directly positioned laterally about a patient 154
illustrated by double arrow 258, such as at the waist of the
patient 154, rather than over the feet or head first.
[0070] A further feature of using a support ring design such as
support rings 216, 216' is that the x-ray source 118 and x-ray
imaging panel 120 can move relative to support rings 216, 216' such
that the components move about the circumference defined by the
support rings and axis 231 without the support ring 216, 216'
itself having to be moved relative to SCARA robot 102. This ability
to move only the x-ray source 118 and x-ray imaging panel 120
relative to support ring 216, 216' can improve precision of the
positioning of the imaging system while reducing the strength of
any motor used to rotate the imaging system. More particularly,
rather than being required to rotate the entire load and over come
the angular inertia of support ring 216, 216' combined with the
x-ray source 118 and x-ray imaging panel 120, only the x-ray source
118 and x-ray imaging panel 120 relative to axis 231 must be
moved.
[0071] FIG. 13 illustrates the ability to move the x-ray source 118
and x-ray imaging panel 120 relative to support ring 216'. In a
preferable embodiment, x-ray source 118 and x-ray imaging panel 120
relative to support ring 216' in both forward and reverse
directions, such as illustrated by double arrows 260, 262 as well
as the dashed representations of x-ray source 118 and x-ray imaging
panel 120.
[0072] Further, in one embodiment, the x-ray source 118 and x-ray
imaging panel 120 may be positioned relative to support ring 216,
216' independently from one another such that the two devices can
move toward one another (typically, they will be positioned along a
diameter of the support ring 216, 216' such that they are equally
spaced in either the clockwise or counter-clockwise directions).
This can be beneficial in the situation where it is desired to use
the x-ray imaging panel 120 in conjunction with beam line x-ray
imaging to align the therapeutic radiation beam.
[0073] Alternatively, in another embodiment, the movement of the
x-ray source 118 and x-ray imaging panel 120 may be coordinated
such that they both move simultaneously about axis 231 the same
amount such that they relative positions of the two devices remains
the same.
[0074] Thus, the use of a support ring 216, 216' provides
substantial improvements in positioning of the imaging positioning
devices relative to a patient for improved precision and usability.
Further, as the SCARA robot 102 is not required to do fine angular
positioning of the entire support structure 116, 116', 216, 216',
the x-ray source 118 and the x-ray imaging panel 120, the overall
strength and power of the SCARA robot 102 can be reduced while
increasing the positioning sensitivity of the imaging system.
[0075] It should be noted that all of the control and safety
features for the D-arm structure 116 embodiments can be
incorporated with the support ring 116 embodiments
[0076] All references, including publications, patent applications,
and patents cited herein are hereby incorporated by reference to
the same extent as if each reference were individually and
specifically indicated to be incorporated by reference and were set
forth in its entirety herein.
[0077] The use of the terms "a" and "an" and "the" and similar
referents in the context of describing the invention (especially in
the context of the following claims) is to be construed to cover
both the singular and the plural, unless otherwise indicated herein
or clearly contradicted by context. The terms "comprising,"
"having," "including," and "containing" are to be construed as
open-ended terms (i.e., meaning "including, but not limited to,")
unless otherwise noted. Recitation of ranges of values herein are
merely intended to serve as a shorthand method of referring
individually to each separate value falling within the range,
unless otherwise indicated herein, and each separate value is
incorporated into the specification as if it were individually
recited herein. All methods described herein can be performed in
any suitable order unless otherwise indicated herein or otherwise
clearly contradicted by context. The use of any and all examples,
or exemplary language (e.g., "such as") provided herein, is
intended merely to better illuminate the invention and does not
pose a limitation on the scope of the invention unless otherwise
claimed. No language in the specification should be construed as
indicating any non-claimed element as essential to the practice of
the invention.
[0078] Preferred embodiments of this invention are described
herein, including the best mode known to the inventors for carrying
out the invention. Variations of those preferred embodiments may
become apparent to those of ordinary skill in the art upon reading
the foregoing description. The inventors expect skilled artisans to
employ such variations as appropriate, and the inventors intend for
the invention to be practiced otherwise than as specifically
described herein. Accordingly, this invention includes all
modifications and equivalents of the subject matter recited in the
claims appended hereto as permitted by applicable law. Moreover,
any combination of the above-described elements in all possible
variations thereof is encompassed by the invention unless otherwise
indicated herein or otherwise clearly contradicted by context.
* * * * *